EuroPCR 2017: Vessel biology matters in BRS design

Results of a five-year shear stress analysis—which combined 3D-angiography and optical coherence tomography (OCT) data—in 15 post-implant patients with BRS, of interest not only for clinicians but also researchers and engineers deepened the understanding of the interaction of bioresorbable scaffold (BRS) with vessel biology.

This session is of great importance for us interventional cardiologists to under-stand more about technical aspects of the devices and consequences of treat-ment for coronary flow and the risk of thrombus formation,” said Clemens von Birgelen, co-chairman of the session.
Erhan Teneke-cioglu, presenter of the study, said that in this analysis he and his colleagues found a heterogeneous shear stress due to protrusion of the struts. “The vessel wall is a dynamic biological structure that tends—at long-term follow-up—to recreate homogeneous and normal shear stress towards physiological values in vessel segments treated with biodegradable scaffolds after full bioresorption and bio-integration,” he concluded.

In another analysis of shear stress by 3D OCT and computational fluid dynamics, Shengxian Tu told participants that low, oscillatory shear stress, and less shear stress spatial heterogeneity “might be in favour of stent coverage after BRS implantation.” S. Tu also noted that “the impact of shear stress, as assessed by this novel approach, on stent healing and neointima hyperplasia warrants further investigation.

Regarding late scaffold thrombosis, Tommaso Gori, presented data analysing its incidence, predictors and mechanisms. In his findings, T. Gori concluded that beyond common clinical predictors, the risk of late scaffold thrombosis is determined by undersizing. Additionally, he said that “OCT evidence of mal-apposition is a predictor of scaffold thrombosis” and highlighted that an appropriate implantation technique “can reduce the risk of late scaffold thrombosis.”  A presentation by Yasuyuki Mizutani investigated an optimal deployment method of polymer BRS to gain acute expansion using a stenotic mechani-cally-equivalent coronary artery model. Y. Mizutani told delegates that in this research he and his colleagues found that prolongation of the total balloon infla-tion time by three repeated inflations was more effective for larger diameter gain, regardless of whether the delivery balloon or a non-compliant balloon were used. Additionally he said that “post-dilatation using a non-compliant balloon after BRS deployment at intermediate balloon inflation pressure was considered feasible to reduce the procedural-related risk of scaffold fracture.